Okay, here's the deal.... Don't listen to the nubs
..... j/k
But seriously. Do NOT pick a crafting profession just now.
You have to put gold into it to level it, instead of making money. And then, before you even pick a prof. consider 2 things..
1. Whats more important, making the money, or the profession bonuses that suit your class/spec.
2. How's the market looking for the professions you are eying, on your realm.
Some stuff is overcrowded and you won't make lick without putting a lot of time and efforts into it. You can be happy to break even with the costs of leveling the profession and the revenue from it later.
Up until endgame crafting professions are pretty obsolete, unless you can specialize in some niche, which requires lots of recipe collecting. And that takes time. A lot of time.
The safe road to make money is a gathering profession.
Herbalism, Mining, Skinning.
Those three will always make you money. Always. It it will be so much money that you can afford to learn every riding skill that you have to learn, up until endgame, plus enough money to fund a crafting profession for basically free.
I actually toyed with that stuff around quite a lot.
I leveled a toon from 0 - 85 in Cata with nothing but gathering. I only did the quests I had to do, like the ones to get into Deepholm, and the few to get to pick up the professions.
And most recently I did the opposite. I leveled a toon up to 80 without any profession. At 80 I grabbed herbs and mining and went to power level them.
The material gathered made me pay all the riding skill money to my main, and I am sitting on 12k profit now with the toon.
All in all, I could have made even more profit, since I had the comparison with the 85 gatherer, who made a ton more.
Skinning seems to be the most profitable profession in regards of material values. But leather isn't needed so much by the crafting professions across the board.
Herbs are needed by Scribes and Alchemists.
Ore needed by Blacksmith, Jewelcrafters and Engineers.